thunderfvck
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Best taper size?
I'm going to be purchasing a distillation set from unitedglassware.com and I can't decide which taper I should buy. Are there any other
benefits for 24/40 besides its large size and larger openings? I guess this is kind of obvious but what do you guys use? What do you think is best? Is
there anything WRONG with 14/20, besides it being smaller? I already own quite a bit of glassware that is 14/20 (a lot of very small stuff, 10 ml
flasks, etc.), but if 24/40 is better then I may just sell all that...
Also, any cheaper sites that sell glassware? This was the cheapest I've found, and don't even mention ebay, I know, I know...
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ziqquratu
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It depends mostly on the volumes that you're intending to distil. 14/20 glassware (and the smaller sizes) are used mostly for microscale
chemistry, where you're distilling mL's of liquid... the largest flask I've seen with 14/20 joints was 100mL. You could, of course,
use adaptors or have flasks specially made, but this could be costly, and you may need to know a glassblower who will do custom work if you want those
flasks. Also, the condensers can be quite short, and can thus be inefficient for large volumes.
Larger sizes, of which 24/40 seems to be the most popular, are generally bad for distilling small amounts, as the mechanical losses can quickly become
unacceptable. These sizes are generally more adaptable, however - I've seen 10mL flasks with 24/40 joints, and of course you can get the larger
flasks with this size joint as standard.
Personally, I have a 19/26 set, which works quite well. The reason I picked this size was that I picked up a couple of cheap items at an auction,
which included a 19/26 Graham condenser and fractionating column... meaning I picked up the most expensive items for a song and could build from
there! However, I found that this size was a pretty good intermediate size - losses on small scale distillations seem to be fairly minimal, while
large volumes can be distilled without too much trouble.
Pretty much, if you want to distil mostly small volumes, 14/20; mostly large-scale distillations would probably call for 24/40; or if you want one set
that does both reasonably well, 19/26 could be the way to go.
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T_FLeX
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I have all 24/40 joints and they are awsome. 24/40 seems to be the most popular and abundant. The majority of the used glassware I have seen for
sale is 24/40 so it might be a good idea to get it if you’re planning on buying used glass later on. Another benefit would be that a lot of the
larger flask don't accept anything smaller than 24/40 except for the 10/30 thermo holes. I’m always seeing huge 24/40 flask on eBay.
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BromicAcid
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While the 24/40 has the advantage of being the considerably more common size it still is worthwhile to consider the 14/20 size if you are not prone to
large batch distillations, just as ziqquratu said loss due to wettening of glass can be considerable with the larger apparatuses so it entirely
depends on just how often you distill large volumes of liquid, plus many reactions of the average chemist are of very tiny amounts anyway. However I
own both a 24/40 setup and a 14/20 setup, usually I use the 24/40 for making up the stock reagents that I keep around, HNO3 and HBr and such and the
lesser glassware for distallation of products CrOCl2 and such. It's all up to you.
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thunderfvck
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Well I ordered a 24/40 set. I think it'll be best. I'm more concerned with making things as of now, maybe not necessarily in bulk but it is
certainly useful for preparing reagents. I think I made a wise decision. I'll just sell the other stuff on ebay, make a buck and buy more 24/40!
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Esplosivo
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How much did the distillation set cost you? What are the components? Thanks
[Edited on 29-3-2004 by Esplosivo]
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thunderfvck
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I ordered it from unitedglasstech.com
It cost me roughly $220 Canadian, it's a complete distillation kit. Minus the thermometer.
Go to the site I listed above and go to the monthly special, you'll see what I ordered. Best deal I've found.
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thunderfvck
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Funny you mentioned it today, because I just got it! Yay!
But I will not start doing all my experiments until summer. I have much work to tend to. And I don't want to play with those delicate RB flasks
without my stands/clamps..
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